The invention relates to a method for determining the weights of liquid units delivered by a dispenser, and a weighing insert and a weighing arrangement for carrying out the method. The weight determination serves for calibrating dispensers, as used in chemical, biological and medical laboratories, with respect to the volume of the liquid units delivered by them.
It is known that dispensers can be calibrated on the basis of a determination of the weights of liquid units delivered by them. In the determination of the weights of very small amounts of liquid, in particular those whose volume is less than 1 xcexcl, the fact that the surface area is very large in relation to the volume leads to a rapid relative decrease in the initial amount of liquid owing to evaporation, which falsifies the result of the weighing.
It is the object of the invention to provide a method of the generic type which permits the reliable determination of the weight of liquid units delivered by a dispenser onto a balance. This object is achieved by the features of the invention. Moreover, it is intended to provide a weighing insert and a weighing arrangement comprising such a weighing insert, which permit the method to be carried out expediently and simply.
In the method according to the invention, the effect of the liquid exchange of the amount of liquid to be weighed and of other components influencing the weighing with the environment is substantially prevented. Errors caused by evaporation or precipitation of liquid are thus eliminated. The weighing insert and the weighing arrangement comprising it enable the method according to the invention to be carried out in a simple and expedient manner.